Composite furnace block



1956 J. E. COFFMAN ET AL COMPOSITE FURNACE BLOCK Filed Dec. 22, 1954 Janus E. CoFl-mfl wa W L40 r0.

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COMPOSITEFURNACE BLOCK James E.,Cotfrnan, Glen Burnie, and Thomas W.'Lloyd,

Pasadena, Md., assignors to Harbison-Walker Refractories Company, Pittsburgh, Pa.,-a corporation of Pennsylvania vApplication December 22,- 1954, Serial No. 477,054

Claims. (Cl. 72-35) This invention relates to'metal casedbasic refractory bricks that are used in industrial. furnaces, and more particularly to .the manner of tightly securing the steel pens, the bricks are usually' broken or otherwise damaged, but even if they are undamaged it may be difficult or impossible for the workmen to fit them back in their cases. A more serious result of the bricks slipping out of their cases is that the bricks may fall on someones feet and cause serious injury, because the bricks are quite heavy.

The bricks themselves are made in two different Ways, distinguished by whether the bricks are merely chemically bonded without firing or whether'they are fired Metal casing in the past has been confined largely to the chemically bonded type of brick, and some methods of easing can be used only with unfired bricks; for example, all processes in which steel cases are attached to bricks while the latter are being formed, such as when the brick batch is 'pressed into a U-shape case in the mold box. Obviously, such bricks must be shipped without firing, since the high temperature necessary for firing them .would destroy thecases by warping or melting them.

Because of the difficulty of making a steel case adhere tightly to a burned brick which'has a substantially unindentable hard surface, cased burned bricks are used very little in the furnace building trade. Nevertheless, the advantages of such a block, should a satisfactory one become available, are well recognized.

It is among the objects of this invention to provide a metal cased basic refractory brick, in which the case is so firmly attached to the brick that there is no danger of their becoming separated, in which steel cases can be securely attached to burned brick as well as to unburned brick, and in which thin gauge metal can be used for the case. Another object is to provide a simple method of joining the case to the brick, whether burned or unburned, in such a way that there will be no danger of their ever becoming separated accidentally.

In accordance with this invention, a multi-part steel case is applied to a basic refractory brick which was either preformed outside of the case or formed in part of the case. During production of the composite block, separate parts of the case are pressed tightly against two opposite sides of the brick, and while the pressure is maintained, those parts of the case are welded together. The result is that a metal case is formed around the tates atent ice 2 brick and it presses so tightly against the brick'that there is no danger of the brick escaping. Preferably, the case is formed from two steel channels having overlapping side flanges.

The invention is illustrated in the accompanying drawings in which:

Fig. 1 is an end view of the composite block;

Fig. 2 is a perspective view,showing schematically the case being applied to the brick; and

Fig. 3 is a side view of a modification of the invention.

Referring toFig. 1 of the drawings, a basic refractory brick 1 is shown inside of a steel case. As is wellknown, the brick may be'made of dead burned'magnesite, chrome ore, olivine or other basic'oxides and blends thereof. Also, the brick may be either fired or unburned, at the time the case is applied to it. The case is made from two parts, each of which preferably consists of a thin sheet metal channel 2. Each channel has a web 3 between a pair of substantially parallel same as the width of the brick, and the width of the side flanges is nearly as great as the thickness of the brick. The two channels can be identical in shape and size if they 'are assembled, as shown, in staggered relation around a preformed brick. 'That is, only one flange of each channel extendsinto the other channel. This results in one outside flange extending downward and the other outside flange extending'upward. The two channels are welded together to form a case, most suitably by spot welds 6 which join the overlapping flanges at each side of the brick. There is a spot weld near the free'corners of each outside flange, whereby the case is welded near diagonally opposite corners. Other Welds may be added if it is felt desirable.

It is a feature of this invention that the case so tightly engages the brick that the brick cannot slide out of the case accidentally and become damaged or injure a workman. Accordingly, immediately before the two channels are Welded together to form the case, the webs 3 of the channels are pressed toward each other and very tightly against the adjoining sides of the brick.

-While this pressure against the brick is maintained, the

overlapping side flanges of the channels are welded together. The welds' 6 prevent-the channels from separating when the pressure against the'webs is removed,

and therefore the'case remains in tight engagement with the brick. Of course, pressure is exerted against the further precaution in case of unburned brick, one or more short tongues 7 may be struck clown into the brick from the web of the upper channel.

The Way in which pressure can be applied to the channels during welding is illustrated in Fig. 2. After a pair of steel channels 2 have been fitted over opposite sides of a brick, the composite block may be placed on a suitable support 19 between two sets of electrodes 11 and 12 and beneath a pressure head or holddown pad 13. The pad is large enough to cover most or all of the top of the block. The pad may be mounted on the lower end of a piston rod 14, the upper end of which extends up into a fluid pressure cylinder 15. The connection 16 between the rod and the pad preferably is a ball type joint to permit the pad to accommodate itself to the block. Fluid pressure is directed to the upper end of the cylinder in any suitable manner to press the pad down against the upper channel. It is preferred to exert about five hundred pounds of pressure against the block to push the upper channel downward and very tightly against the top of the brick. The upper side flanges will slide downward across the lower flanges and the brick will be pressed equally tightly against the web of the lower channel. While the high pressure is maintained on the brick by the hold-down pad, the electrodes are moved inwardly with considerable pressure to spot-weld the corners of the outer flanges against the inner flanges 4. The electrodes shown in Fig. 2 have iust spot-welded the case and been retracted to show the welds 6. When the hold-down pad is raised, the welds prevent the upper channel from rising and relieving the pressure against the brick, and therefore the case remains very tightly engaging the brick.

upper end of each punch is provided with a head 19 between which and the top of the boss there is a coil spring 20 that normally holds the lower end of the punch at least as high as the lower surface of the pad. If it is desired to provide the case with anchor tongues, the heads of the punches may be struck by a hammer or by any suitable mechanical device to cause the metal to be pierced and tongues bent down into the brick. This is done while the hold-down pad is pressing tightly against the block. After the steel case has been formed, the hold-down pad is raised and the metal cased brick or composite block is removed from beneath it and is ready for use.

In the modification shown in Fig. 3, the side flanges 22 and 23 of the steel channels 24 do not overlap like those just described, but have their free longitudinal edges spaced apart so that there will be no chance of their coming together and preventing the webs of the channels being forced tightly against the upper and lower sides of the brick 25. To permit the flanges at each side of the brick to be welded together while the channels are under pressure, the longitudinal edge of each flange has at least two laterally offset positions 26 and 27 connected by a step or edge 28 perpendicular thereto or transverse to the brick. The transverse edges of each pair of flanges 22 and 23 substantially engage each other and are welded together at 29 while the channels are under pressure, thereby forming a tight metal case around the brick.

Much thinner metal can be used for our channels than heretofore when only one channel was used and the spring in its flanges was depended on to grip a brick. Therefore, even though there is a double thickness of metal at two opposite sides of the brick, the total thickness need be no more than the thickness of single channels used before. The thinner gauge channels of this invention also are easier to form and to apply to bricks than heavier channels were. Of course, the bricks do not have to be rectangular.

According to the provisions of the patent statutes, we have explained the principle of our invention and have illustrated and described what we now consider to represent its best embodiment. However, we desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

We claim:

l. A composite furnace block comprising a basic r fractory brick, a pair of steel channels having well very tightly engaging two opposite sides of the brick and having side flanges covering the other two sides of the brick, and welds joining the flanges at each of said last-mentioned sides to form a metal case tightly enclosing the brick.

2. A composite furnace block comprising a basic re fractory brick, a pair of steel channels having webs very tightly engaging two opposite sides of the brick and having side flanges covering the other two sides of the brick, the flanges at each of said last-mentioned sides having spaced free longitudinal edges, each of said edges having laterally offset portions connected by a transverse edge, said transverse edges of adjoining flanges being substantially in engagement with each other, and welds joining the pairs of transverse edges to form a metal case tightly enclosing the brick.

3. A composite furnace block comprising a basic refractory brick, a pair of steel channels having webs very tightly engaging two opposite sides of the brick and having overlapping side flanges at the other two sides of the brick, and welds joining the two overlapping flanges at each of said last-mentioned sides to form a metal case tightly enclosing the brick.

4. A block in accordance with claim 3, in which the brick is preformed and one side flange of each channel is located next to the brick.

5. A block in accordance with claim 3, in which the brick is preformed and one side flange of each channel is located next to the brick, and said welds are located near the longitudinal edge of the outer-flanges, whereby the welds are near diagonally opposite corners of the case.

References Cited in the file of this patent UNITED STATES PATENTS 874,724 Barker Dec. 24, 1907 2,247,376 Heuer July 1, 1941 2,652,793 Heuer et a1 Sept. 22, 1953 FOREIGN PATENTS 690,898 Great Britain Apr. 29, 1953 

1. A COMPOSITE FURNACE BLOCK COMPRISING A BASIC REFRACTORY BRICK, A PAIR OF STEEL CHANNELS HAVING WEBS VERY TIGHTLY ENGAGING TWO OPPOSITE SIDES OF THE BRICK AND HAVING SIDE FLANGES COVERING THE OTHER TWO SIDES OF THE BRICK, AND WELDS JOINING THE FLANGES AT EACH OF SAID LAST-MENTIONED SIDES TO FORM A METAL CASE TIGHTLY ENCLOSING THE BRICK. 